Tipos especiais histológicos de carcinomas da mama : perfil imunoistoquímico com ênfase na classificação molecular / Histological special types of breast carcinomas : immunohistochemical profile with emphasis on molecular classification

AUTOR(ES)
FONTE

IBICT - Instituto Brasileiro de Informação em Ciência e Tecnologia

DATA DE PUBLICAÇÃO

16/12/2011

RESUMO

Most invasive breast carcinomas are classified as invasive ductal carcinoma, not otherwise specified (IDC-NOS), while approximately 25% are defined as special histological types (HST). These HST of breast carcinomas are categorized into at least 17 distinct pathological entities. Most studies in the literature regarding the molecular classification (luminal A and B, HER2- overexpression, "basal-like") were evaluated only in IDC-NOS and in lobular invasive carcinoma, a study with more HST of breast carcinoma would be necessary. The CK19 can be used as a method of evaluation of sentinel lymph node using a molecular technique called OSNA (one step acid nucleic amplification). The expression of CK19 positivity was assessed only in ductal, lobular, medullary and small cell carcinomas. It was performed tissue microarray (TMA) in IPATIMUP (Porto-Portugal) of 157 cases selected from the archives of the Instituto de Patologia de Campinas, a private laboratory. A total of 121 and 116 TMA cases in the molecular profiling and in the CK19 studies was obtained, respectively, including tubular, mucinous, papillary encapsulated and invasive, lobular, micropapillary, medullary, metaplastic, apocrine and mixed carcinomas. It was used immunohistochemical markers such as ER, PR, RA (only in apocrine carcinomas), HER2, Ki67, P-cadherin, CK5, EGFR and p63 to classify them as the molecular classification and as the CK19 expression in the breast before performing the technique of OSNA in sentinel lymph node. Tubular, papillary and mucinous were all luminal A and B, as similar as the geneexpression profiling; medullary and metaplastic were almost all "basal-like" (76.2% and 90%, respectively), while at transcriptome level, all cases belong to subtype "basal-like"; micropapillary was luminal A and B and HER2- overexpression and in the transcriptomic level was virtually all luminal B due to high expression of HER2; apocrine was the most heterogeneous tumours of our study with luminal A and B, HER2-overexpression and "basal-like" cases. This data was different from transcriptomic level that revealed the "molecular apocrine" subtype (RE-/ RA+/ HER2- or +). The relative risk of Ki67 increased between HST, because medullary carcinomas had 110 times more risk of increased Ki-67 than tubular carcinomas. The CK19 was expressed in 98.2% of HST of breast carcinomas, data identical to the Chu et al study, and the positivity increased in cases where the entire paraffin block had been fully studied, because its labeling was focal in many cases evaluated on TMA. This CK19 focal expression can produce false-negative results in the breasts "corebiopsies"

ASSUNTO(S)

mamas - câncer imunoistoquímica biópsia excisão de linfonodo breast cancer immunohistochemistry biopsy lymph node excision

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